For many decades it has been attempted to develop socalled "shell-less" ammunition. By shell-less it is meant that after the firing of the cartridge, no shell need be separately removed from the weapon. Thus the cartridge can consist only of the projectile and the completely burning charge connected with it. However, it has been found that such ammunition leads to difficulties in actual practice; the catridges are very sensitive to impact and therefore unsuitable for automatic weapons, since the charge breaks or detaches itself from the bullet, and in addition there is the danger of self-ignition upon introduction of the cartridge into the weapon which is hot from previous firing. Finally, such ammunition is extremely sensitive to external influences.
For this reason it has been attempted to protect the propellant charge from these effects.
In particular, the projectile has been extended towards the rear in the form of a hollow body which receives the propellant charge. This made the manufacture of the cartridge more difficult and resulted in an unfavorable shape of the projectile. Furthermore, this solution is in opposition to the desire to decrease ther weight of the cartridge to a minimum in order to increase the readiness for firing and, for a given weight, to increase the number of shots which can be carried.
A large number of such solutions have been discussed in the article "Shell-Less Ammunition for Small Arms and Machine Guns" in the Wehrtechnische Monatshefte 1956, page 366.
German Offenlegungschrift No. 1,958,925 describes a cartridge having a shell of plastic; this construction is therefore not shell-less in the sense of entirely eliminating the presence of a shell, but satisfies the aforementioned requirements, since, while the shell is not consumed, it is ejected automatically through the barrel of the gun by the propellant gases and accordingly need not be withdrawn from the breech.
In this cartridge, the full-caliber projectile is forced into a depression in the open side of the shell or bonded therein; the diameter of the shell thus exceeds the caliber of the weapon (barrel-bore diameter) by a considerable amount. To this extent there is similarity with the customary cartridges. Under the action of the gases of the propellent charge, the shell is destroyed and discharged through the barrel of the gun; in order to assure this, a predetermined break point is provided. The danger that parts will remain in barrel is always present with this cartridge.
This construction has various disadvantages. First, the shooting results may not be reproducible, since the energy required for the expulsion and prior crushing of the shell tends to vary from shot to shot. One important disadvantage is that despite bonding to the plastic shell, the projectile can detach itself from the shell, particularly if, in case of misfire, the cartridge must be removed from the chamber since the projectile can then jam in the riflings of the barrel.